Intraocular Pressure (IOP) is an extremely important characteristic of a physical state of the eye, especially in glaucoma patents. Nearly one percent of the total population of the United States suffers from this form of blindness. Glaucoma is characterized by an increase in IOP which causes visual defects and ultimately may cause irreversible blindness. As the IOP rises to abnormal levels, damage is caused to the ocular nerve and surrounding retinal tissues. The patient seldom experiences any symptoms that might indicate that the disease exists until major damage occurs.
As part of many standard eye examinations, a test of IOP known as tonometry is performed to detect the early stages of glaucoma. Tonometry broadly relates to the measurement of tension in living tissue and has special meaning in ophthalmology relating to IOP and the health of the eye. Pressure in the eye is not measured directly, but is typically inferred by measuring the eye's response to pressure exerted upon the cornea.
A measure of the pressure within the eye is conventionally obtained by indenting to a given depth or flattening to a given extent a portion of a measurement surface of the eye, usually the cornea, and then determining the amount of force required to produce the given flattening or indentation. The flattening or indentation is resisted by the resiliency of the measurement surface and by the internal pressure of the eyeball. The determined force is then converted to a measurement of IOP.
In some occasions, health care professionals are required to assess IOP digitally (i.e., with their fingertip). The ability to digitally determine IOP is critical in trauma cases where time is of the essence and proper measuring devices may not be available. Additionally, measuring devices may not be available in some locations. It has been proven that a minimal amount of training allows a health care professional to accurately assess IOP digitally. In the past, this type of training has been done on cadaveric human or animal eyes which has many drawbacks, among them being the problems associated with obtaining and maintaining human or animal tissue over long periods of time and to eliminate any possibility of disease transmission from contaminated samples.